1. Field of the Invention
This application is directed to oil-soluble load-carrying additives consisting of polyesters of certain polysulfideorganocarboxylic acids useful in various lubricant compositions comprising oils of lubricant viscosity or greases prepared therefrom. Partially oxidized derivatives, i.e., where one or more of the sulfide groups is oxidized, to a sulfoxide or sulfone of the above-described polyesters also possess good load-carrying characteristics.
2. Description of the Prior Art
It is known to use organic sulfur compounds as additives for lubricating oils. These compounds provide extreme pressure properties to lubricants, however, the presence of sulfur in lubricating oils can cause corrosion of metal parts in contact with the lubricant. Oil-insolubility of some organic sulfur compounds is an additional problem.